1. Field of the Invention
The invention relates in general to solid deposition modeling, and in particular to a method and managing power consumption in a selective deposition modeling apparatus so as to make the apparatus viable in an office environment.
2. Description of the Prior Art
Recently, several new technologies have been developed for the rapid creation of models, prototypes, and parts for limited run manufacturing. These new technologies are generally called Solid Freeform Fabrication techniques, and are herein referred to as xe2x80x9cSFF.xe2x80x9d Some SFF techniques include stereolithography, selective deposition modeling, laminated object manufacturing, selective phase area deposition, multi-phase jet solidification, ballistic particle manufacturing, fused deposition modeling, particle deposition, laser sintering, and the like. Generally in SFF techniques, complex parts are produced from a modeling material in an additive fashion as opposed to conventional fabrication techniques, which are generally subtractive in nature.
In most SFF techniques, structures are formed in a layer by layer manner by solidifying or curing successive layers of a build material. For example, in stereolithography a tightly focused beam of energy, typically in the ultraviolet radiation band, is scanned across a layer of a liquid photopolymer resin to selectively cure the resin to form a structure. In Selective Deposition Modeling, herein referred to as xe2x80x9cSDM,xe2x80x9d a build material is typically jetted or dropped in discrete droplets, or extruded through a nozzle, in order to solidify on contact with a build platform or previous layer of solidified material in order to build up a three-dimensional object in a layerwise fashion. Other synonymous names for SDM which are used in this industry are solid object imaging, solid object modeling, fused deposition modeling, selective phase area deposition, multi-phase jet modeling, three-dimensional printing, thermal stereolithography, selective phase area deposition, ballistic particle manufacturing, fused deposition modeling, and the like. Ballistic particle manufacturing is disclosed in, for example, U.S. Pat. No. 5,216,616 to Masters. Fused deposition modeling is disclosed in, for example, U.S. Pat. No. 5,340,433 to Crump. Three-dimensional printing is disclosed in, for example, U.S. Pat. No. 5,204,055 to Sachs et al. Often a thermoplastic material having a low-melting point is used as the solid modeling material in SDM, which is delivered through a jetting system such as an extruder or print head. One type of SDM process which extrudes a thermoplastic material is described in, for example, U.S. Pat. No. 5,866,058 to Batchelder et al. One type of SDM process utilizing ink jet print heads is described in, for example, U.S. Pat. No. 5,555,176 to Menhennett et al.
Recently, there has developed an interest in utilizing curable materials in SDM. One of the first suggestions of using a radiation curable build material in SDM is found in U.S. Pat. No. 5,136,515 to Helinski, wherein it is proposed to selectively dispense a UV curable build material in an SDM system. Some of the first UV curable material formulations proposed for use in SDM systems are found in Appendix A of International Patent Publication No. WO 97/11837, where three reactive material compositions are provided. More recent teachings of using curable materials in various selective deposition modeling systems are provided in U.S. Pat. No. 6,259,962 to Gothait; U.S. Pat. Nos. 6,133,355 and 5,855,836 to Leyden et al; U.S. Pat. App. Pub. No. U.S. 2002/0016386 A1; and International Publication Numbers WO 01/26023, WO 00/11092, and WO 01/68375.
For SDM systems that selectively dispense curable materials, a radiation curing step is needed to initiate the curing process. Radiation curing exposure systems whether they are curing.
One of the advantages of first generation SDM machines that worked with thermoplastic waxes to build objects was that the machines could be used in an office environment. These wax dispensing SDM systems consumed not much more power than other office equipment such as photocopier, and could therefore operate on conventional power requirements found in an office, such as 20A/115V service.
However, SDM systems dispensing curable materials require a radiation curing exposure system in order to initiate the curing process. These systems, typically flash curing or continuous flood systems, consume a significant amount of power when they are activated, such that when combined with the power consumed by other systems within the SDM apparatus, the overall power consumed by the apparatus exceeds conventional power limits found in an office. Thus, power consumption must be kept at a minimum so as to meet conventional power limitations as well as a power management system to assure these limitations are not exceeded.
Thus, there is a need to develop a power management system for use in an SDM apparatus capable of maintaining the average power consumption of the machine within the acceptable limits of an office environment. These and other difficulties of the prior art have been overcome according to the present invention.
The present invention provides its benefits across a broad spectrum. While the description which follows hereinafter is meant to be representative of a number of such applications, it is not exhaustive. As will be understood, the basic methods and apparatus taught herein can be readily adapted to many uses. It is intended that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed.
It is one aspect of the present invention to provide a power management system for an SDM apparatus that adapts the apparatus for use in any office environment.
It is another aspect of the present invention to provide a power management system that prevents the SDM apparatus for exceeding a baseline power consumption value when in operation in any office environment.
It is a feature of the present invention that a hierarchical list is generated of the power drawing components that need to be activated, in which only those that can be activated without exceeding the baseline power consumption value are activated.
It is another feature of the present invention that when one high power drawing component is activated all other power drawing components are de-activated.
It is an advantage of the present invention that an SDM apparatus can be utilized in all office environments without the need of a transformer or other power storing devices.
These and other aspects, features, and advantages are achieved/attained in the method and apparatus of the present invention. The present invention method of power management for a selective deposition modeling apparatus comprises: measuring a divergence from a desired effect to be achieved in the apparatus for each power drawing component, determining which components need to be activated based on a comparison of the measured divergence and an acceptable threshold effect for each component, sorting the components that need to be activated into a list, determining from the list the number of power consuming components that can be activated without exceeding the baseline power consumption value; and activating the components. Once a steady state condition for the apparatus is achieved, one of the power drawing components which draws a substantial amount of power when activated is activated while all other components are de-activated so that the baseline power consumption value is not exceeded.
The selective deposition modeling apparatus for forming a three-dimensional object comprises a support means affixed to the apparatus for supporting the three-dimensional object in the build environment; a dispensing means affixed to the apparatus and in communication with the support means for dispensing the curable material in the build environment according to the computer data to form the layers of the three-dimensional object; a flash exposure means affixed to the apparatus for curing the dispensed material, the flash exposure means in communication with the support means; a plurality of power drawing components, each component having an activation power rating wherein the accumulative total of all the power ratings exceeds a baseline power consumption value of the apparatus; and a power management system. The power management system maintains the amount of power consumed by the plurality of power drawing components below a baseline power consumption value. Further, the power management system adapted to: measure the divergence from a desired effect to be achieved in the apparatus by each component, determine which components need to be activated based on a comparison of the measured divergence and an acceptable threshold effect for each component, sort the components that need to be activated into a list; determine from the list the number of power consuming components that can be activated without exceeding the baseline power consumption value, and activate the components.